1. Field of the Invention
The present invention relates to transition of a mainframe of a computer to an open system. More specifically, the present invention relates to a technique for converting a job written in JCL for a mainframe to a job network for an open system.
2. Description of the Related Art
Recently, many business firms are actively making transitions from the mainframe that has been used to open systems using general-purpose OS such as UNIX (registered trademark) and Windows (registered trademark) in order to cut TCO (Total Cost of Ownership) that is the cost required for maintenance and operation of computer systems used for the business transactions. For that, it is necessary to convert jobs written in “Job Control Language” (referred to as JCL hereinafter) which is used to be operated on the mainframe into a job network (flowchart and divided JCL files) for open systems, and then to convert those into a script file.
FIG. 22 is an explanatory diagram showing an example of a job network. FIG. 22A-FIG. 22D are all flowcharts which illustrate the same sequential relations. In most of typical job management tools, there is no restriction set in terms of descriptions so as to allow users to write the jobs in any writing styles. However, with such systems, flowcharts may often become different as in FIG. 22A-FIG. 22D depending on personal habits of the users even for the flowcharts expressing the same sequential relation. To have mixtures of various flowcharts in different forms but showing the same sequential relation may results in inefficiency when conducting tests at the time of transition of the jobs, maintenance after the transitions, and the like.
In the flowchart shown in FIG. 22A, for overcoming such issue, a start point and an end point are fixed in advance, and the way of drawing the line of flowchart is limited on the many-purpose job management software side. With this, the flowcharts come to be in a same form no matter who draws the flowchart. Thus, it is possible to create a simple job network flow of high maintenance property. When transiting the business system from the mainframe to the open system, the JCL file is converted into a job network (flowchart and divided JCL files), and then converted to a script file by using such job management software.
As a technique related to this, there are following patent documents. Japanese Unexamined Patent Publication Hei 07-248915 (Patent Document 1) discloses a technique generates a syntax tree by parsing a program, and relates declaration, assignments, and the like for each data name to the data use conditions. Japanese Unexamined Patent Publication Hei 08-016378 (Patent Documents 2) discloses a technique which parses a program, extracts blocks configured with a series of statements not including divergence, and expresses those hierarchically along with the divergence and merging sections. Japanese Unexamined Patent Publication Hei 11-024913 (Patent Document 3) discloses a technique which sorts out a program written in JCL by a line unit, and then converts it into a program of another form.
However, there are parallel execution instruction such as a sentence “¥SUBJOB - - - ¥ENDSUBJOB” and an order control instruction such as a sentence “¥WHEN - - - JUMP” sentence (if - - - goto) in JCL. Depending on the sense of the creator, those instructions may be used frequently. FIG. 23 is an explanatory diagram showing an example of a JCL file in which such parallel execution instructions and order control instructions are used frequently.
When such parallel executions instruction and order control instructions are used in JCL file frequently as shown in FIG. 23, it is difficult to grasp the accurate sequential relation from the line numbers. Thus, it becomes difficult to convert the file into a flowchart mechanically by utilizing an automatic conversion tool or the like. Even if it can be done, a complicated job network of low maintenance property may be generated.
Therefore, conversion of such JCL file to a job network has mainly been done manually. This requires a great deal of labor, and the quality of the created job network depends on the skill of the worker. Further, this my causes increase in the cost due to the degradation in the quality generated by human errors and due to the recovery work thereof.
If the JCL does not contain the parallel execution instructions or the order control instructions, conversion from the JCL file to the job network can be done easily. Therefore, if it is possible to detect the parallel execution instructions and the order control instructions from the JCL file and create a flowchart, and possible to divide the JCL file by excluding the parallel execution instructions or the order control instructions, the aforementioned issue can be overcome. However, Patent Documents 1-3 mentioned above do not disclose such techniques for dividing the JCL file, so that it is not possible with those to overcome this issue.